Naslov
Microscopic origin of the scattering pre-peak in aqueous propylamine mixtures

Autori
Požar, Martina ; Almásy, László ; Lovrinčević, Bernarda ; Baptista, Anthony ; Perera, Aurélien

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, ostalo, znanstveni

Skup
4th Grandmaster Early-Career Workshop in Physics

Mjesto i datum
Split, Hrvatska, 01.09.2019. - 07.09.2019

Vrsta sudjelovanja
Poster

Vrsta recenzije
Nije recenziran

Ključne riječi
Binary-mixture ; molecular-dynamics ; scattering-experiments ; propylamine-water ; scattering-intensity

Sažetak
The structure of aqueous propylamine mixtures is investigated through X-ray and neutron scattering experiments, and the scattered intensities compared with computer simulation data. Both sets of data show a prominent scattering pre-peak, which first appears at propylamine mole fraction x ≥ 0.1 around scattering vector k ≈ 0.2Å−1, and evolves towards k ≈ 0.8Å−1 for neat propylamine x = 1. The existence of a scattering pre-peak in this mixture is unexpected, specifically in view of its absence in aqueous 1-propanol or aqueous DMSO mixtures. The detailed analysis of the various atom-atom structure factors and snapshots indicates that significant micro-structure exists, which produces correlation pre-peaks in the atom-atom structure factors, positive for like species atoms correlations and negative for the cross species ones. The scattering pre-peak depends on how these two contributions cancel or not. The way the amine group bond with water, produce a pre-peak through the inbalance of the positive and negative scattering contributions, unlike 1-propanol and DMSO, where these 2 contributions compensate exactly. Hence molecular simulations demonstrate how chemical details influence the microscopic segregation in different types of molecular emulsions and can be detected or not by scattering experiments.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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